ya, light heat and oxygen degrade it into a nonactive isomer, so the best thing would be wrap it in saran wrap, tin foil, stick it in a book, put it a cold dark closet, that is assuming it is blotter and that you cant freeze it
so will a week be fine? Can you get it and then take it within the next few days without worrying, or what?
A friend of mine left a blotter in his top drawer for about 3 or 4 months (Hoffman milinium- strong trips). I ate it and worked just as well as when we first got them. Once when living in tropical north Australia I got a sheet of 100 sent up in the post- I used to keep them behind the family portrait, inside the picture frame- they lasted for months until we ate them all. As long as it's dry- liquid will kill your acid and avoid direct sunlight.
it will be fine. also, in the freezer it will last ages. i know a friend who buys acid only rarely. he keeps it stored very well and takes a few doses per year from his stash.
Just don't take it in and out of the freezer for extended periods. Take it out, get what you need, put it back in.